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I decided to repaint my girlfriends starter bike for the experience of it (and nothing could be worse than what was on there - can job)

I used single stage paint from NAPA. Did all the prep and shot the paint - nice and shiney with a few little bubbles. I wet sanded the bubles down with a 1500 wet sand and now I can't get the shine back. I tried the 3M polishmade to take out 1200 and finer sand marks.

I used the correct amount of hardner and waited 48 hours to do the wet sand and polish.

The paint is smooth, but is lacking the shine it hand before the sanding.

what am i doing wrong?
 

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I've used PPG DCC single stage in the past it's probably close to the NAPA. I wet sanded with 2000 before polishing. I found that hand polishing just didn't work to get a good shine. I needed to use a polisher with a good foam pad (egg cage type) with either 3M or Ultra cutting cream to bring back the shine. The polisher puts more heat into the paint which helps, just need to be careful not to burn through.
 

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Did you use a high speed polisher, from Vduc's response it sounds like you did not. If thats the case then I second the motion on that. Confirm you used a 3M product that claims it can remove 1200 grit?

After using 1500 sand paper, it may be advisable to color sand with 2000. This "staging" will enable you to remove the sand marks without resorting to using compounds that are too aggressive and therefore leaving behind unsightly swirl marks. What you are doing is knocking down the heavier sand scratches. The key is to remove the color sanding marks without leaving heavy swirl. As Vduc indicated, it is imperative to use a variable RPM high speed buffer. There are many chemical compounds available that will work, especially when you work the paint within the recommended time frame. If you work it too early you'll experience dye back scratches, it you work it too late the paint will be hard as rock and difficult to buff. Anyway, use the least aggressive compound and buff pad to get the job done. If you can get away with a foam pad, great, but in reality the wool or better yet a wool blend pad is the way to go. The wool will remove the color sand scratches quickly, then simply polish out the fine swirl with a foam pad and appropriate polish or glaze. Depending on the paint, sometimes you can get away with a two step process, but personally, I like to three step it for that perfect finish.
RPMs between 1750 - 2400 when compounding and 1000 - 1750 when finishing. It takes skill to use the high speed buffer, there is no way you can achieve optimum results by hand.
 

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John, thanks for the tips on the wool bonnets and polisher speeds. My preference is to basecoat/clearcoat since I'm doing my track bikes and like to layout the different colors all in one day. Does that apply to base/clear? Are you in the paint business?

I'm just an amateur hack that like to paint my own stuff.
 

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I've done some and think you are working too hard. A good clear coat is all you need, no buffing. It's best to do a few dryer layers and a final wet coat. But beware of the toxicity of the two part clears in a typical base coat/clear coat system, simply put, don't breathe them. It might be better to spray and wet sand the base coats and take it to an auto painter to clear it.
 

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Great info on this thread - thanks!

I always go for a single stage paint since it's easier to deal with when it comes time for repairs (no clear coat layer to deal with).
 

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Hank you're right on the repair part, but I gave up crashing this year :)

I typically don't do any color sanding or polishing on my base coat/clear coat paint jobs especially since it's on track bikes.

Definitely don't breathe the stuff, I put on 3M mask that is approved for spray paint before I even open the can for mixing.

For my most recent paint job I build a "spray booth" with PVC pipe, plastic tarps, and some furnace/AC filters with a fan attached for circulation, cut down on 99% of over spray dust in the garage.
 

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Discussion Starter #8
Heading to the track - I'll let you guys know how your tips worked out!
 
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